This invention relates to cartridges and cassettes for retaining light sensitive material, and more particularly to such cartridges and cassettes provided with a protected key code.
Cartridges for insertion into utilization apparatus have been provided with discrete encoding portions, such as protrusions, slots and/or holes, are arranged in such a manner that an undesired or improper cartridge could not be inserted or placed into the utilization device and inadvertently used. Further, encoding information has been provided on cartridges for the purpose of identifying a characteristic of the material contained within the cartridge, which characteristic is read and interpreted or used by the utilization apparatus.
Prior devices which have been designed to prevent the inadvertent utilization of a cartridge or cassette have had the disadvantage that they are unreliable and often can be defeated. Also, the encoding arrangement did not provide a variety of codes, and did not provide a fail-safe structure in the event of attempted forced use or cheating.